(1) Two-way call: host could call extension freely, extension also could call host.(2)Talkback: it needn’t transform when speaking and hearing, both sides could talk with each other, as convenient as telephone.(3)Host and extension could be reset.(4) Display screen with large four high-brightness digital tube.(5) The small screen of showing treatment situation has the same cue music as host.(6) Store and automatically queue the number of extension when calling.(7) Twelve polyphonic songs are optional for host’s ringing, and volume of ringing is adjustable with 16 series.(8) Extension could call consistently without interruption: if an extension call host when host is talking with the other, the host could receive and display the new call signal without interrupting present conversation.(9) Function of intensive care priority: host could be set a several extensions with intensive care priority. When many extensions call, the extension with intensive care priority could prior to others.(10)Short circuit alarm: when line is short circuit, the host’s digital tube displays the letters of "DL" with alarm ringing.(11) Could fix the extension with toilet urgent call.